K-cymrite
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Formula:
KAlSi3O8 · H2O
range of hydration states is present
Crystal System:
Hexagonal
Isostructural with:
The K analogue of cymrite. An ultra-high-pressure(UHP) phase, stable above 2.5 GPa and 600oC, and up to 9 GPa at 1200oC. First observed in an experiment (Seki & Kennedy, 1964) as a product of hydration of sanidine. Crystallization is possible when ca. equimolar amounts of water are present. When the water amount exceeds that of the KAlSi3O8 molecule, melting occurs leading to corundum, kyanite and muscovite.
Compare the closely related anhydrous kokchetavite.
Compare the closely related anhydrous kokchetavite.
Unique Identifiers
Mindat ID:
47681
Long-form identifier:
mindat:1:1:47681:0
IMA Classification of K-cymrite
IMA status notes:
Published without approval
Chemistry of K-cymrite
Mindat Formula:
KAlSi3O8 · H2O
range of hydration states is present
range of hydration states is present
Element Weights:
Crystallography of K-cymrite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mmm
Cell Parameters:
a = 5.3361(3) Å, c = 7.7081(7) Å
Ratio:
a:c = 1 : 1.445
Unit Cell V:
190.08 ų
Comment:
Data from Romanenko et al. (2021).
Geological Environment
Geological Setting:
Dulan eclogite (replaced by polycrystalline K-feldspar aggregates)
Radioactivity
Other Information
Notes:
Raman band at 390-395 cm-1 (typical of the cymrite structure)
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for K-cymrite
mindat.org URL:
https://www.mindat.org/min-47681.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
References for K-cymrite
Reference List:
Zhang, R. Y., Liou, J. G., Iizuka, Y., Yang, J. S. (2009) First record of K-cymrite in North Qaidam UHP eclogite, Western China. American Mineralogist, 94 (2) 222-228 doi:10.2138/am.2009.2983
Romanenko, Alexandr V., Rashchenko, Sergey V., Sokol, Alexander G., Korsakov, Andrey V., Seryotkin, Yurii V., Glazyrin, Konstantin V., Musiyachenko, Kira (2021) Crystal structures of K-cymrite and kokchetavite from single-crystal X-ray diffraction. American Mineralogist, 106 (3) 404-409 doi:10.2138/am-2020-7407
Korsakov, Andrey V., Romanenko, Alexandr V., Sokol, Alexander G., Musiyachenko, Kira A. (2023) Raman spectroscopic study of the transformation of nitrogen‐bearing K‐cymrite during heating experiments: Origin of kokchetavite in high‐pressure metamorphic rocks. Journal of Raman Spectroscopy, 54 (11) 1183-1190 doi:10.1002/jrs.6541
Localities for K-cymrite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| DOI: 10.2138/am.2009.2983 +2 other references |
Kazakhstan | |
| Mikhno et al. (2013) |